An Exploratory, Observational Cohort Study on the Dynamics of Heparin Binding Protein in Cardiothoracic Surgery Using Cardiopulmonary Bypass

Abstract

BackgroundSurgical trauma and cardiopulmonary bypass (CPB) cause an inflammatory response, difficult to differentiate from postoperative infections. Heparin-binding protein (HBP) is released from neutrophils and has been shown to predict infection-related organ dysfunction and disease progression to severe sepsis. In order to explore the potential of HBP as a biomarker for postoperative infections and asess possible confounding effects of concomitant medications, this study aimed to investigate the pre-, intra- and postoperative dynamics of HBP in cardiac surgery with CPB.Methods Thirty patients undergoing cardiac surgery with CPB were included, of which 15 underwent coronary artery bypass grafting (CABG) surgery and 15 underwent complex procedures with longer CPB duration. Ten patients undergoing lung surgery without CPB were also included as a conventional surgery reference group. HBP was measured at nine different perioperative time points.Results Our results showed that HBP levels were not affected by surgical trauma by itself. An increase in HBP levels was observed immediately following heparin administration and further increased during CPB. Prior to protaminization, we measured higher peak HBP-levels in the complex group (345.7 (287.8-472.6) ng/mL) compared with the CABG group (152.7 (85.3-204.0) ng/mL, p<0.001). HBP decreased rapidly following cessation of CPB and simultaneous protamine administration. Delay of protamine administration revealed that protamine, and not the cessation of CPB is primarily responsible for the rapidly reduced HBP concentration. At the arrival to the ICU, the median HBP levels were 24.8 (15.6-38.1) ng/mL for CABG patients compared with 50.5 (36.5-104.6) ng/mL for complex surgery patients (p=0.004). One day after surgery, HBP levels in all three groups were below the proposed cutoff of 30 ng/mL, previously found to predict development of organ dysfunction during infection, while other biomarkers for infections remained elevated.ConclusionsHBP levels are elevated by administration of heparin and the use of CPB but reduced by protamine administration. At postoperative day one, HBP levels were below the threshold for infection with organ dysfunction, indicating that postoperative HBP measurement may be a better screening tool for postoperative infections than other biomarkers of infections that remain elevated after surgery.